1014P - Response to chemotherapy in ovarian cancer (OC) patients with or without prior breast cancer (BC), stratified by BRCA mutation (BRCAm) status

Abstract

BackgroundWomen with OC due to an underlying BRCAm have enhanced responses to platinum and often improved progression free survival. BRCAm carriers also have an increased risk of BC, which often predates OC and may impact later treatment response. MethodsWomen with OC treated at The Royal Marsden Hospital between 01/06/13 and 31/5/17 with known BRCAm status were identified from the electronic patient record. The primary endpoint was progression free survival (PFS) after first line treatment for OC, stratified for BRCAm and BC status. Secondary endpoints were time to second subsequent treatment (TSST) and type of BRCA mutation (BRCA1 vs BRCA2). Results575 patients were identified, 502 high grade (HG), 73 low grade (LG) OC. Histology was HG serous (77%), endometroid (10%), clear cell (5%), LG serous (4%), other (4%). 158 (27%) had a BRCAm, 92 (58%) BRCA1 and 66 (42%) BRCA2. Mean age of OC diagnosis was 59 (19-98) yrs. Prior BC was noted in 79 patients – 51 BRCAm, 28WT; 21 patients had >1 BC (14 BRCA, 7WT). Mean age of first BC diagnosis was 50 yrs (30-75). Median PFS (mths) was 19.6 (BC, WT) vs 23.6 (no BC, WT) vs 25.4 (BC, BRCAm) vs 27.1 (no BC, BRCAm), p=0.08. TSST(mths) was significantly different at 23.1 (BC, WT) vs 30 (no BC, WT) vs 34 (BC, BRCAm) vs 42.6 (no BC, BRCAm), p=0.02. There was no significant difference in PFS between those who did/did not receive chemotherapy for prior breast cancer; nor between those with a BRCA1 vs BRCA2 mutation. ConclusionsWithin the limits of a retrospective audit, there was no significant difference in PFS for women with OC irrespective of prior BC diagnosis or BRCAm status, but there was a significant difference in TSST. A similar trend was seen in both groups, with poorest PFS/TSST in those with prior BC/BRCA WT; and best PFS/TSST in those with no prior BC/BRCAm. Prior BC diagnosis may be another factor in response to OC chemotherapy. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.